Frame Cap (#124)

docs/new-features.md

@@ -148,4 +148,6 @@ migrated once into `options.lua` on load.
   hotkey `2` (OG RED = GBC boot-ROM look; RED++ uses pokered-gbc
   SuperPalettes + per-species mon colors)
 - TILT (OFF / 15 / 35 / 50),  also hotkey `3` while free-roaming
-- GBC FX (OFF / 1 / 2 / 3 / 4),  also hotkey `5`
+- GBC FX (OFF / 1 / 2 / 3 / 4),  also hotkey `5`
+- MAX FPS (30 / 40 / 50 / 60 / 75 / 90 / 100 / 120 / 144 / 160, default 60),
+  a hard render frame-rate cap (`save.options.fpsCap`).

main.lua

@@ -299,3 +299,78 @@ function love.filedropped(file)
   end
   if Importer then Importer:filedropped(file) end
 end
+
+local function pacingEnabled()
+  if os.getenv("POKEPORT_AUTOPILOT") then return false end
+  if os.getenv("POKEPORT_DRIVER") then return false end
+  if os.getenv("POKEPORT_IMPORT_ONLY") == "1" then return false end
+  return true
+end
+
+function love.run()
+  if love.load then love.load(love.arg.parseGameArguments(arg), arg) end
+
+  -- don't let love.load's cost land in the first frame's dt
+  if love.timer then love.timer.step() end
+
+  local FrameCap = require("src.core.FrameCap")
+  local paced = pacingEnabled()
+  -- The deadline the next present() should not beat.  Carried forward one
+  -- budget per frame so pacing stays even instead of drifting with the
+  -- per-frame sleep-granularity jitter.
+  local nextFrame = love.timer and love.timer.getTime() or 0
+  local dt = 0
+
+  return function()
+    -- process events
+    if love.event then
+      love.event.pump()
+      for name, a, b, c, d, e, f in love.event.poll() do
+        if name == "quit" then
+          if not love.quit or not love.quit() then
+            return a or 0
+          end
+        end
+        love.handlers[name](a, b, c, d, e, f)
+      end
+    end
+
+    -- update dt
+    if love.timer then dt = love.timer.step() end
+
+    -- call update and draw
+    if love.update then love.update(dt) end
+
+    if love.graphics and love.graphics.isActive() then
+      love.graphics.origin()
+      love.graphics.clear(love.graphics.getBackgroundColor())
+      if love.draw then love.draw() end
+      love.graphics.present()
+    end
+
+    if love.timer then
+      if paced then
+        -- Sleep out the remainder of the frame budget, measured from the
+        -- carried deadline, in small chunks so the OS timer stays
+        -- responsive.  vsync is untouched: when it already paces slower
+        -- than the cap the remainder is <= 0 and this rounds to a no-op.
+        local budget = 1 / FrameCap.current
+        nextFrame = nextFrame + budget
+        local now = love.timer.getTime()
+        -- A stall (alt-tab, a GC pause, a blocked import) can leave the
+        -- deadline more than a full budget in the past; re-anchor to now so
+        -- we pace the next frame rather than burst uncapped to catch up.
+        if now - nextFrame > budget then
+          nextFrame = now
+        end
+        while true do
+          local remaining = nextFrame - love.timer.getTime()
+          if remaining <= 0 then break end
+          love.timer.sleep(remaining < 0.001 and remaining or 0.001)
+        end
+      else
+        love.timer.sleep(0.001)
+      end
+    end
+  end
+end

src/core/FrameCap.lua

@@ -0,0 +1,72 @@
+-- Render frame-rate cap.  With a driver control panel forcing
+-- vsync off, the 160x144 game is trivially cheap and love.run will present
+-- thousands of frames a second; over hours that cooks the graphics driver
+-- until a restart, and it wastes power whenever the window is left open in
+-- the background.  A hard cap bounds the present rate.  Render-only: game
+-- logic is fixed-step off dt (src/core/FixedStep.lua), so pacing present()
+-- changes nothing about timing, audio, or determinism.
+--
+-- Persisted as save.options.fpsCap; applied from OptionsMenu and on boot
+-- via Game:applyOptions.  main.lua's love.run reads FrameCap.current each
+-- frame for its sleep budget.  The module never touches love.timer itself,
+-- so it stays safe under the headless test stub.
+
+local FrameCap = {}
+
+-- Selectable steps: the normal framerate stops between the floor and the
+-- ceiling.  STEPS[1] == MIN and STEPS[#STEPS] == MAX, so the nearest-step
+-- snap in normalize doubles as the clamp.  Cycling past the last wraps.
+FrameCap.STEPS = { 30, 40, 50, 60, 75, 90, 100, 120, 144, 160 }
+FrameCap.MIN = 30
+FrameCap.MAX = 160
+FrameCap.DEFAULT = 60
+
+-- The live cap the run loop paces to.  Defaults so the launcher and the
+-- save editor are paced before any save applies its stored option.
+FrameCap.current = FrameCap.DEFAULT
+
+-- Nearest valid step for an arbitrary value (a hand-edited options.lua or
+-- an old save with no fpsCap key), so a bad number degrades to something
+-- sane; nil / non-numbers fall back to the default.  A value below MIN or
+-- above MAX snaps to that end, since MIN/MAX are the first/last steps.
+function FrameCap.normalize(value)
+  value = tonumber(value)
+  if not value then return FrameCap.DEFAULT end
+  local best, bestDiff = FrameCap.DEFAULT, math.huge
+  for _, step in ipairs(FrameCap.STEPS) do
+    local diff = math.abs(step - value)
+    if diff < bestDiff then best, bestDiff = step, diff end
+  end
+  return best
+end
+
+-- plain numeric text for the options row (e.g. "60")
+function FrameCap.label(value)
+  return tostring(FrameCap.normalize(value))
+end
+
+-- cycle to the next/previous step, wrapping (the options row idiom)
+function FrameCap.cycle(value, dir)
+  local steps = FrameCap.STEPS
+  local snapped = FrameCap.normalize(value)
+  local cur = 1
+  for i, step in ipairs(steps) do
+    if step == snapped then cur = i break end
+  end
+  local nextIdx = (cur - 1 + (dir or 1)) % #steps + 1
+  return steps[nextIdx]
+end
+
+-- Store the chosen cap as the live value the run loop paces to.  Never
+-- touches love.timer, so it is safe headless -- the loop just reads the
+-- number back.  Returns the normalized value it stored.
+function FrameCap.apply(value)
+  FrameCap.current = FrameCap.normalize(value)
+  return FrameCap.current
+end
+
+function FrameCap.applyOptions(opts)
+  FrameCap.apply(opts and opts.fpsCap)
+end
+
+return FrameCap

src/core/Game.lua

@@ -445,6 +445,9 @@ function Game:applyOptions(opts)
   require("src.render.Tilt").applyOptions(opts)
   require("src.render.GBCFX").applyOptions(opts)
   require("src.core.VideoMode").applyOptions(opts)
+  -- normalizes a nil/garbage cap to the 60 default, so old saves with no
+  -- fpsCap key pace at the standard rate (issue #88)
+  require("src.core.FrameCap").applyOptions(opts)
   Input:applyBindings(opts.bindings)
 end
 

src/core/SaveData.lua

@@ -192,6 +192,8 @@ function SaveData.defaultOptions()
     gbcfx = 0,
     -- windowed | borderless (desktop fullscreen); ignored on mobile
     videoMode = "windowed",
+    -- hard render frame-rate cap; render-only pacing (issue #88, FrameCap.lua)
+    fpsCap = 60,
     -- Native mod enablement is an installation option, not save-slot data.
     -- Missing entries mean enabled so newly installed mods work by default.
     mods = {},

src/ui/OptionsMenu.lua

@@ -13,6 +13,7 @@ local Tilt = require("src.render.Tilt")
 local GBCFX = require("src.render.GBCFX")
 local GameSpeed = require("src.core.GameSpeed")
 local VideoMode = require("src.core.VideoMode")
+local FrameCap = require("src.core.FrameCap")
 local Logger = require("src.core.Logger")
 local Runtime = require("src.mods.Runtime")
 local OptionRows = require("src.ui.OptionRows")
@@ -202,6 +203,19 @@ local function buildRows(game)
         VideoMode.apply(o.videoMode)
         return true
       end },
+    -- hard render cap (issue #88): bounds the present rate so a
+    -- driver-forced vsync-off run cannot spin at thousands of FPS.  Logic
+    -- is fixed-step off dt, so this touches presentation only.
+    { id = "fpsCap", label = "MAX FPS",
+      value = function(g)
+        return FrameCap.label(g.save.options.fpsCap)
+      end,
+      step = function(g, dir)
+        local o = g.save.options
+        o.fpsCap = FrameCap.cycle(o.fpsCap, dir)
+        FrameCap.apply(o.fpsCap)
+        return true
+      end },
     -- fast-forward the logic clock only; music and sfx keep their tempo
     -- (src/core/GameSpeed.lua), so this is safe to leave on
     { id = "speed", label = "GAME SPEED",

tests/mod_ui_tests.lua

@@ -22,6 +22,7 @@ local StateStack = require("src.core.StateStack")
 local ManagerState = require("src.mods.ManagerState")
 local ModUI = require("src.ui.ModUI")
 local Theme = require("src.ui.Theme")
+local FrameCap = require("src.core.FrameCap")
 
 local savedEvents, savedHooks, savedErrors =
   Runtime.events, Runtime.hooks, Runtime.errors
@@ -205,7 +206,7 @@ end
 local om = OptionsMenu.new(optGame())
 local WANT_IDS = { "textSpeed", "animations", "battleStyle", "ruleset",
                    "musicVol", "sfxVol", "musicFilter", "colors", "tilt",
-                   "gbcfx", "videoMode", "speed", "mods", "controls" }
+                   "gbcfx", "videoMode", "fpsCap", "speed", "mods", "controls" }
 check(#om.rows == #WANT_IDS, "vanilla options row count (plus MODS/CONTROLS)")
 for i, id in ipairs(WANT_IDS) do
   check(om.rows[i].id == id, "options row order: " .. id)
@@ -235,10 +236,47 @@ check(om.game.save.options.musicVol == 6, "music volume steps down")
 for _ = 1, 10 do om.rows[5].step(om.game, -1) end
 check(om.game.save.options.musicVol == 0, "music volume clamps at 0")
 
+-- the MAX FPS row cycles the render-cap steps and shows the value plain
+om.game.save.options.fpsCap = nil
+check(om.rows[12].value(om.game) == "60",
+  "MAX FPS row defaults to 60 with no saved cap")
+om.rows[12].step(om.game, 1)
+check(om.game.save.options.fpsCap == 75, "MAX FPS steps up from 60 to 75")
+check(om.rows[12].value(om.game) == "75", "the MAX FPS row renders the cap")
+om.game.save.options.fpsCap = 160
+om.rows[12].step(om.game, 1)
+check(om.game.save.options.fpsCap == 30, "MAX FPS wraps past the ceiling to 30")
+om.rows[12].step(om.game, -1)
+check(om.game.save.options.fpsCap == 160, "MAX FPS wraps back down to the ceiling")
+
+-- ------- FrameCap normalize / cycle (issue #88)
+check(FrameCap.normalize(nil) == 60, "FrameCap defaults nil to 60")
+check(FrameCap.normalize("junk") == 60, "FrameCap defaults garbage to 60")
+check(FrameCap.normalize(60) == 60, "FrameCap keeps an exact step")
+check(FrameCap.normalize(58) == 60, "FrameCap snaps 58 to the nearest step 60")
+check(FrameCap.normalize(72) == 75, "FrameCap snaps 72 to the nearest step 75")
+check(FrameCap.normalize(0) == 30, "FrameCap clamps below the floor to 30")
+check(FrameCap.normalize(9999) == 160, "FrameCap clamps above the ceiling to 160")
+check(FrameCap.normalize(30) == 30 and FrameCap.normalize(160) == 160,
+  "FrameCap keeps the exact floor and ceiling")
+check(FrameCap.label(nil) == "60" and FrameCap.label(144) == "144",
+  "FrameCap.label renders the normalized cap as plain text")
+check(FrameCap.cycle(60, 1) == 75, "FrameCap cycles 60 up to 75")
+check(FrameCap.cycle(60, -1) == 50, "FrameCap cycles 60 down to 50")
+check(FrameCap.cycle(160, 1) == 30, "FrameCap cycle wraps the ceiling to the floor")
+check(FrameCap.cycle(30, -1) == 160, "FrameCap cycle wraps the floor to the ceiling")
+check(FrameCap.cycle(nil, 1) == 75,
+  "FrameCap cycle normalizes a nil cap (60) before stepping")
+-- apply drives the live value the run loop paces to; never touches love.timer
+FrameCap.apply(144)
+check(FrameCap.current == 144, "FrameCap.apply stores the live cap")
+FrameCap.applyOptions({})
+check(FrameCap.current == 60, "FrameCap.applyOptions defaults a missing key to 60")
+
 -- the MODS row is the manager's discoverable home
 local mgGame = optGame()
 om = OptionsMenu.new(mgGame)
-om.rows[13].activate(mgGame)
+om.rows[14].activate(mgGame)
 check(getmetatable(mgGame.stack:top()) == ManagerState,
   "the MODS row opens the manager")
 check(mgGame.stack:top().screenId == "ManagerState",
@@ -248,7 +286,7 @@ check(mgGame.stack:top().screenId == "ManagerState",
 local BindingsMenu = require("src.ui.BindingsMenu")
 local cbGame = optGame()
 om = OptionsMenu.new(cbGame)
-om.rows[14].activate(cbGame)
+om.rows[15].activate(cbGame)
 local bm = cbGame.stack:top()
 check(getmetatable(bm) == BindingsMenu,
   "the CONTROLS row opens the rebind list")

tests/run_tests.lua

@@ -2091,6 +2091,7 @@ do
   local GBCFX = require("src.render.GBCFX")
   local GameSpeed = require("src.core.GameSpeed")
   local VideoMode = require("src.core.VideoMode")
+  local FrameCap = require("src.core.FrameCap")
   local SD = require("src.core.SaveData")
   -- Isolate from earlier save/options writes in this suite
   SD.saveOptions(SD.defaultOptions())
@@ -2155,7 +2156,16 @@ do
   eq(og.save.options.videoMode, "windowed",
      "VIDEO MODE wraps back to WINDOWED")
   press("down")
-  eq(om.index, 12, "cursor reaches GAME SPEED")
+  eq(om.index, 12, "cursor reaches MAX FPS")
+  press("a")
+  eq(og.save.options.fpsCap, 75, "A cycles MAX FPS up from 60 to 75")
+  eq(FrameCap.current, 75, "the live render cap tracks the MAX FPS option")
+  -- Driven by the step list rather than a literal press count, like GAME
+  -- SPEED below: a full loop of #STEPS presses returns to the 60 default.
+  for _ = 1, #FrameCap.STEPS - 1 do press("a") end
+  eq(og.save.options.fpsCap, 60, "MAX FPS wraps back to 60")
+  press("down")
+  eq(om.index, 13, "cursor reaches GAME SPEED")
   press("a")
   eq(og.save.options.speed, 2, "A cycles GAME SPEED to 2X")
   -- Driven by the level list rather than a literal press count: adding a
@@ -2164,19 +2174,19 @@ do
   for _ = 1, #GameSpeed.LEVELS - 1 do press("a") end
   eq(og.save.options.speed, 1, "GAME SPEED wraps back to NORMAL")
   press("down")
-  eq(om.index, 13, "cursor reaches MODS")
+  eq(om.index, 14, "cursor reaches MODS")
   press("down")
-  eq(om.index, 14, "cursor reaches CONTROLS")
+  eq(om.index, 15, "cursor reaches CONTROLS")
   press("down")
-  eq(om.index, 15, "CANCEL stays the fixed final row")
-  eq(om.scroll, 10, "CANCEL keeps the last option boxes on screen")
+  eq(om.index, 16, "CANCEL stays the fixed final row")
+  eq(om.scroll, 11, "CANCEL keeps the last option boxes on screen")
   om:draw() -- smoke: scrolled layout draws under the headless stub
   press("a")
   check(popped, "A on CANCEL closes the options menu")
   local om2 = OptionsMenu.new(og)
   OInput.pressed = { up = true }; om2:update(1 / 60); OInput.pressed = {}
-  eq(om2.index, 15, "up from the top wraps to CANCEL")
-  eq(om2.scroll, 10, "wrapping to CANCEL scrolls to the tail")
+  eq(om2.index, 16, "up from the top wraps to CANCEL")
+  eq(om2.scroll, 11, "wrapping to CANCEL scrolls to the tail")
   -- headless-safe: no love.audio, setters only update internal state
   require("src.core.Music").applyOptions(og.save.options)
   require("src.core.Sound").applyOptions(og.save.options)